The XF-R 400-1 is a passive near-field probe. In principle it has the same structure as the XF-R 100-1 and XF-R 3-2 probes. The near-field probe is small and handy. It has a current attenuating sheath and, therefore, is electrically shielded. It can be connected to a spectrum analyzer or an oscilloscope with a 50 Ω input. The H-field probe has an internal terminating resistance.